In handover scenarios of existing mobile communications systems, a handover procedure is usually triggered by a user equipment (User Equipment, UE). During communication with a currently connected serving node, a UE periodically measures pilot signal strength of a neighboring node. After pilot signal strength of the serving node deceases to below a preset threshold and meanwhile the pilot signal strength of the neighboring node increases to above the preset threshold and stays for a specific time, a handover procedure is triggered. At present, a UE uses an A3 event for handover judgment. The A3 event includes the following two handover conditions, which respectively are:Condition for entry: Mn+Ofn+Ocn−Hys>Mp+Ofp+Ocp+Off; andCondition for leave: Mn+Ofn+Ocn+Hys<Mp+Ofp+Ocp+Off, 
where, M is a parameter measured by a UE with respect to a node and may be reference signal received power (Reference Signal Received Power, RSRP) or reference signal received quality (Reference Signal Received Quality, RSRQ); the subscript n indicates that the parameter is related to a neighboring node; the subscript p indicates that the parameter is related to a serving node; Ofn indicates an offset related to a carrier of the neighboring node; Ocn indicates an offset related to coverage of the neighboring node; Ofp indicates an offset related to a carrier of the serving node; Ocp indicates an offset related to coverage of the serving node; and Hys and Off are design parameters, where Hys is a hysteresis. In addition, the preceding parameters are all measured in decibels (dB).
Mobile communications systems of the 3rd Generation Partnership Project (3rd Generation Partnership Project, 3GPP) apply a coordinated multiple point (Coordinated Multiple Point, CoMP) technology, and the CoMP technology is one of important technologies for a system to increase coverage at network edges and ensure quality of service (Quality of Service, QoS) for edge UEs. When the CoMP technology is implemented, multiple nodes coordinate to provide services for a same UE, which increases system throughput. Evolved base stations (E-UTRAN NodeB, eNB) are used in a 3GPP mobile communications system. According to a multi-antenna diversity theory, one eNB can access multiple remote radio headers (Remote Radio Header, RRH), where each RRH can be regarded as a node.
FIG. 1 shows a CoMP work scenario, where an eNB is a primary node and 6 low-power RRHs are disposed under the primary node, and the RRHs can be used as secondary nodes. Each RRH has its own identity (ID). The eNB and the RRHs form a CoMP macro serving cell, and in the macro serving cell, UEs can receive a CoMP service provided by the eNB and the RRHs in coordination. When a UE stays within a service range of a macro serving cell, the macro serving cell provides functions similar to those of the above-mentioned serving node. In addition, the macro serving cell also has other secondary nodes and therefore, in the macro serving cell, the UE has multiple serving nodes.
When a UE moves from a macro serving cell to a macro neighboring cell, a handover procedure needs to be triggered. The current 3GPP mobile communications systems, however, do not stipulate handover policies specific to the foregoing CoMP work scenario. As a result, where there is a need for handover, a UE still uses the A3 event for handover judgment. During the handover, related parameters of a neighboring node need to be measured. In the foregoing CoMP handover scenario, the UE randomly selects a node in the macro neighboring cell, measures related parameters of the node, and uses a measurement result as a criterion for judgment of an A3 event-based handover. The communication effect is unsatisfactory after a handover is performed by using such a handover method. According to test data, system throughput decreases substantially after such a handover because the node measured in the macro neighboring cell is selected randomly.